AASHTO T 157-2012 Standard Method of Test for Air-Entraining Admixtures for Concrete.pdf

《AASHTO T 157-2012 Standard Method of Test for Air-Entraining Admixtures for Concrete.pdf》由会员分享，可在线阅读，更多相关《AASHTO T 157-2012 Standard Method of Test for Air-Entraining Admixtures for Concrete.pdf（9页珍藏版）》请在麦多课文档分享上搜索。

1、Standard Method of Test for Air-Entraining Admixtures for Concrete AASHTO Designation: T 157-12 (2016) Release: Group 1 (April 2016) ASTM Designation: C233/C233M-10a American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-

2、3b T 157-1 AASHTO Standard Method of Test for Air-Entraining Admixtures for Concrete AASHTO Designation: T 157-12 (2016) Release: Group 1 (April 2016) ASTM Designation: C233/C233M-10a 1. SCOPE 1.1. This method covers the testing of materials proposed for use as air-entraining admixtures in the field

3、. 1.2. The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information purposes only. 1.3. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to esta

4、blish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.4. The text of this standard references notes and footnotes that provide explanatory materials. These notes and footnotes (excluding those in tables and figures) shall not be consi

5、dered as requirements of the standard. 2. REFERENCED DOCUMENTS 2.1. AASHTO Standards: M 6, Fine Aggregate for Hydraulic Cement Concrete M 80, Coarse Aggregate for Hydraulic Cement Concrete M 85, Portland Cement M 154M/M 154, Air-Entraining Admixtures for Concrete M 240M/M 240, Blended Hydraulic Ceme

6、nt R 39, Making and Curing Concrete Test Specimens in the Laboratory R 60, Sampling Freshly Mixed Concrete T 22, Compressive Strength of Cylindrical Concrete Specimens T 27, Sieve Analysis of Fine and Coarse Aggregates T 97, Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading)

7、T 119M/T 119, Slump of Hydraulic Cement Concrete T 137, Air Content of Hydraulic Cement Mortar T 152, Air Content of Freshly Mixed Concrete by the Pressure Method T 158, Bleeding of Concrete T 160, Length Change of Hardened Hydraulic Cement Mortar and Concrete T 161, Resistance of Concrete to Rapid

8、Freezing and Thawing T 196M/T 196, Air Content of Freshly Mixed Concrete by the Volumetric Method T 197M/T 197, Time of Setting of Concrete Mixtures by Penetration Resistance 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violatio

9、n of applicable law.TS-3b T 157-2 AASHTO 2.2. ASTM Standards: C33/C33M, Standard Specification for Concrete Aggregates C136/C136M, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates C185, Standard Test Method for Air Content of Hydraulic Cement Mortar C670, Standard Practice for P

10、reparing Precision and Bias Statements for Test Methods for Construction Materials C1157/C1157M, Standard Performance Specification for Hydraulic Cement D75/D75M, Standard Practice for Sampling Aggregates E70, Standard Test Method for pH of Aqueous Solutions With the Glass Electrode Manual of Aggreg

11、ate and Concrete Testing 2.3. ACI Standard: ACI 211.1-91, Recommended Practice for Selecting Proportions for Normal, Heavy-Weight and Mass Concrete 3. SIGNIFICANCE AND USE 3.1. This test method is used to develop data for comparison with the requirements of M 154M/M 154. These tests are based on arb

12、itrary stipulations permitting highly standardized testing in the laboratory and are not intended to simulate actual job conditions. 4. MATERIALS 4.1. Cementitious MaterialThe cementitious material used in any series of tests shall meet any of the following: 4.1.1. The cementitious material proposed

13、 for specific work in accordance with Section 4.4, portland cement conforming to the specifications for either Type I, Type II, or Type III M 85 hydraulic cement, conforming to the specification of ASTM C1157/C1157M; 4.1.2. Blended hydraulic cement conforming to the specification of M 240M/M 240. If

14、 a blend of cements is used, it shall be a combination that produces an air content of less than 10 percent when tested in accordance with T 137 (Note 4). 4.2. AggregatesExcept when tests are made in accordance with Section 4.4, using the aggregates proposed for specific work, the fine and coarse ag

15、gregates used in any series of tests shall come from single lots of well-graded, sound materials that conform to the requirements of M 6 and M 80, except that the grading of the aggregates shall conform to the following requirements: 4.2.1. Fine Aggregate GradingThe fine aggregate shall meet the req

16、uirements for the fine aggregate in ASTM C33/C33M. Sieve Percentage Passing 4.75 mm (No. 4) 100 1.18 mm (No. 16) 65 to 75 0.300 mm (No. 50) 15 to 20 0.150 mm (No. 100) 2 to 5 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violatio

17、n of applicable law.TS-3b T 157-3 AASHTO 4.2.2. Coarse Aggregate GradingThe coarse aggregate shall meet the requirements for Size 57 of ASTM C33/C33M (Note 1). Note 1Take care in loading and delivery to avoid segregation. 4.2.3. The coarse aggregate used for the reference concrete and test concretes

18、 shall be essentially the same. Provide sufficient coarse aggregate for the reference concrete, the test concrete, and for the grading analysis. Concrete consists of one reference concrete and as many test admixture-containing concretes as are intended to be compared. 4.2.4. Prepare required quantit

19、ies of coarse aggregate as follows: Fill tared containers, one for sieve analysis, one for a batch of reference concrete, and one for a batch of test concrete, to the required mass from the aggregate stockpile (see Note 2). Accomplish this by placing equal quantities into each container, successivel

20、y, and repeat the procedure until all the containers have their required mass (see Note 2). Note 2See the Appendix of ASTM D75/D75M, Sampling from Stockpiles, and the section on Sampling Aggregates in ASTMs Manual of Aggregate and Concrete Testing for guidance on procedures for sampling from stockpi

21、les. 4.2.5. Perform sieve analysis on the coarse aggregate sample prepared by T 27. Discard any set for which the sample does not comply with No. 57. Average test results for samples that comply with No. 57 for each sieve size. Discard any set for which the sample deviates from this average by more

22、than the amount shown in Column 3. Continue the process of preparation, testing, and averaging until sufficient sets of aggregate within tolerance are obtained (see Note 3). Note 3All of the results required for demonstrating compliance under this specification are dependent on the uniformity of the

23、 aggregate samples prepared and used. Careful, skilled, and well-supervised work is essential. Sieve ASTM C33/C33M No. 57, Percent Passing Maximum Variation from Average/Passing 37.5 mm 100 0.0 25.0 mm 95 to 100 1.0 12.5 mm 25 to 60 4.0 4.75 mm 0 to 10 4.0 2.36 mm 0 to 5 1.0 4.3. Reference Admixture

24、For this method, unless otherwise requested by the purchaser, the reference admixture used in the concrete mixture specified in Section 5 shall be “neutralized Vinsol resin.”14.4. Materials for Tests for Specific UsesWhen it is desired to test an air-entraining admixture for use in specific work, th

25、e cementitious material and aggregates used should be representative of those proposed for use in the work, and the concrete mixtures should be designed to have the cementitious material content specified for use in the work (Note 4). If the maximum size of coarse aggregate is greater than 25.0 mm (

26、1 in.), the freshly mixed concrete shall be screened over a 25.0-mm (1-in.) sieve prior to fabricating the test specimens in accordance with the wet sieving procedure described in R 60. When other admixtures are intended to be used in the production of concrete, they should be included in the trial

27、batch. 4.5. Preparation and Mass DeterminationAll materials shall be prepared and all mass determinations shall be made as prescribed in R 39. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 157-

28、4 AASHTO Note 4It is recommended that whenever practicable, tests be made in accordance with Section 4.4 using the cementitious materials and chemical admixtures, if any, proposed for specific work. 5. CONCRETE MIXTURES 5.1. ProportionsUsing ACI 211.1-91, all concrete shall be proportioned to confor

29、m to the following requirements: 5.1.1. The cement content shall be 307 3 kg/m3(517 5 lb/yd3) except when tests are being made for specific uses (Section 4.4). 5.1.2. The first trial mixture shall contain the amount of coarse aggregate shown in Table 6.3.6 of ACI 211.1-91 for the maximum size of agg

30、regate and for the fineness modulus of the sand being used. Note 5The volumes of coarse aggregate in Table 6.3.6 of ACI 211.1-91 are intended to assure workable mixtures with the least favorable combinations of aggregate likely to be used. It is suggested that for a closer approximation of the propo

31、rtions required for this test, the recommended values selected from Table 6.3.6 be increased by about 7 percent for the first trial mixture. 5.1.3. The air content used in the computation of proportions for all concrete shall be 5.5 percent except where the admixture under test is for use in specifi

32、c work (Section 4.4). In this case, the air content used in selecting proportions shall be the median of the range to be permitted in the work. If lightweight aggregates are to be used in specific work, the unit mass of concrete used in selecting proportions shall be the median of the range permitte

33、d in the work. 5.1.4. The water content and sand content shall be adjusted to obtain a slump of 89 13 mm (3.5 0.5 in.). The workability of the concrete mixture shall be suitable for consolidation by hand rodding and the concrete mixture shall have the minimum water content possible. These conditions

34、 shall be achieved by final adjustments in the proportion of fine aggregate to total aggregate, in the amount of total aggregate, or both, while maintaining the yield and slump in the required ranges. 5.2. ConditionsConcrete mixtures shall be prepared both with the air-entraining admixture under tes

35、t and with the reference admixture. The admixtures shall be added in the amounts necessary to produce the air content selected in accordance with Section 5.1.3 within a tolerance of 0.5 percent of the volume of concrete. 6. MIXING 6.1. Machine mix the concrete as prescribed in R 39. 7. TESTS AND PRO

36、PERTIES OF FRESHLY MIXED CONCRETE 7.1. Test samples of freshly mixed concrete from at least three separate batches for each condition of concrete in accordance with the following methods. The minimum number of tests shall be as prescribed in Table 1. 7.1.1. SlumpRefer to T 119M/T 119. 2016 by the Am

37、erican Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 157-5 AASHTO 7.1.2. Air ContentRefer to T 152. When lightweight aggregates, air-cooled blast furnace slag, or aggregates are used under the provisions of Section

38、 4.4, use T 196M/T 196. 7.1.3. BleedingRefer to T 158. 7.1.4. Time of SettingRefer to T 197M/T 197, except that the temperature of each of the ingredients of the concrete mixtures, just prior to mixing, and the temperature at which the time of setting specimens are stored during the test period shal

39、l be 23.0 1.7C (73.4 3F). Table 1Types and Minimum Number of Specimens and Tests Test Number of Types of SpecimensaNumber of Test Ages Number of Conditions of ConcretebMinimum Number of Specimens Slump 1 1 2 c Air content 1 1 2 c Bleeding 1 1 2 6 Time of setting 1 d 2 6 Compressive strength 1 3 2 18

40、 Flexural strength 1 3 2 18 Freezing and thawing 1 1 2 12eLength change 1 1 2 6 aSee Sections 7 and 9.2. bSee Section 4.2. cDetermined on each batch of concrete mixed. dSee Section 7.1.4. eSpecimens for duplicate tests from each batch. 8. PREPARATION OF TEST SPECIMENS 8.1. Specimens for tests of har

41、dened concrete, representing each test and age of test and each condition of concrete being compared, shall be made from at least three separate batches, and the minimum number of specimens shall be as prescribed in Table 1. On a given day, at least one specimen shall be made for each test and age o

42、f test from each condition of concrete, except that at least two specimens for the freezing and thawing test shall be made from each condition of concrete. The preparation of all specimens shall be completed in 3 days of mixing. 8.2. Manifestly Faulty SpecimensEach group of specimens representing a

43、given test or a given age of test, including tests of freshly mixed concrete, shall be examined visually before or during the test, or both, whichever is appropriate. Discard any specimens found to be manifestly faulty by such examination without testing. Visually examine all specimens representing

44、a given test at a given age after testing and should any specimen be found to be manifestly faulty, the test results thereof shall be disregarded. Should more than one specimen representing a given test at a given age be found manifestly faulty, either before or after testing, the entire test shall

45、be disregarded and repeated. The test result reported shall be the average of the individual test results of the specimens tested or, in the event that one specimen or one result has been discarded, it shall be the average of the test results of the remaining specimens. 9. TEST SPECIMENS OF HARDENED

46、 CONCRETE 9.1. Number of SpecimensMake six or more test specimens for the freezing and thawing test and three or more test specimens for each other type of test and age of test specified in Table 1 for each condition of concrete to be compared. 2016 by the American Association of State Highway and T

47、ransportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b T 157-6 AASHTO 9.2. Types of SpecimensPrepare specimens made from concrete with and without the air-entraining admixture under test in accordance with the following: 9.2.1. Compressive StrengthMake and cu

48、re test specimens in accordance with R 39. 9.2.2. Flexural StrengthMake and cure test specimens in accordance with R 39. 9.2.3. Resistance to Freezing and ThawingTest specimens shall consist of prisms made and cured in accordance with the applicable requirement of R 39. Test specimen dimensions shal

49、l be as required by T 161. Make one set of specimens from the concrete mixture containing the air-entraining admixture under test and from the reference concrete mixture, the air content of each mixture being as specified in Section 5.2. 9.2.4. Length ChangeMake and cure test specimens in accordance with T 160. The moist-curing period, including the period in the molds, shall be 14 days. 10. TESTS ON HARDENED CONCRETE 10.1. Test specimens of hardened concrete in accordance with the follo